UniversalIDE
Add-on based IDE adaptable to any developement platform
...Anyone who knows the .NET Framework can develop add-ons to support a programming language, defining syntax highlighting rules and interfacing the IDE with compilers or interpreters. It is written in Visual Basic .NET, so it requires the .NET Framework to run.
The program's GUI is multi-language (actually English and Italian are officially supported, but translating to another language is as easy as editing an XML file).
More information in the wiki https://sourceforge.net/p/universalide/wiki/ and in the website http://universalide.sf.net
This project uses SharpZipLib: http://icsharpcode.github.io/SharpZipLib/
Some icons are from this creative commons - licensed icon set: http://p.yusukekamiyamane.com/ .